Obsessive Compulsive Disorder (OCD) is a chronic and debilitating disorder known to have reported lifetime prevalence in the range of 2%. OCD is most commonly treated with Cognitive Behavioural Therapy (CBT) and/or pharmacotherapy. However, some studies suggest challenges with CBT in retaining gains long term, and while 60-80% of OCD patients respond to SRI treatment, partial symptom reduction is substantial. Investigations into the effectiveness of alternative, cost-effective treatment modalities are thus needed. Mindfulness, defined as paying attention in a particular way (on purpose, in the present moment and nonjudgmentally), promotes awareness and attention to internal experience and has been shown to reduce symptoms of anxiety and depression. A number of controlled studies have found Mindfulness-Based Cognitive Therapy (MBCT) to be effective for depression, social anxiety disorder, and generalized anxiety disorder, but few have tested its effect on obsessive compulsive disorder (OCD). Moreover, those studies examining MBCT in OCD focused on clinical case studies and non-clinical samples. This study proposes to examine the effect of MBCT in clinical practice, in a randomized sample of patients with OCD whom are on a clinic wait list. As patients are allocated to the wait list, they will be randomly assigned to receive either 10 weeks of group MBCT or wait list as per usual. It is hypothesized that subjects randomly assigned to the MBCT treatment group, compared to those in the wait list control group, will see greater reductions in self-reported measures of OCD symptom severity and improvement in other measures of mindfulness, mood and level of functioning. The results of this pilot study, if successful, will provide evidence towards another route by which patients can improve their OCD while waiting for clinic services or consultation. Results will also lend more evidence as to whether MBCT is effective as a stand-alone treatment for clinical OCD, which will inform further investigations into the potential addition of mindfulness techniques to standard care.

Inclusion Criteria:

• Referred for treatment services at the Frederick W. Thompson Anxiety Disorder Centre at Sunnybrook Health Sciences Centre
• Primary Diagnosis of OCD
• Ability to communicate in written and spoken English

Exclusion Criteria:

• Those with active substance abuse/dependence within 3 months
• Suspected organic pathology
• Recent suicide attempt/active suicidality
• Current self-injurious behaviour
• Active bipolar or psychotic disorder
• Previous completion of an MBCT course (≥ 8 weeks)
• Previous completion of an OCD-specific course of CBT (≥ 8 weeks)
• Previous completion of a general course of CBT (≥ 8 weeks) in the past 3 years